A “hybrid cloud” is a cloud infrastructure composed of two or more clouds that inter-operate or federate. A hybrid cloud can be an interaction between private and public clouds where a private cloud connects to a public cloud and utilizes public cloud resources in a secure and scalable way. The hybrid cloud model provides key advantages over others cloud models. For example, the hybrid cloud model allows enterprises to protect their existing investment; maintain control of their sensitive data and applications; and maintain control of their network, computing, and storage resources. Additionally, hybrid clouds allow enterprises to scale their environment on demand.
While many applications are suited for corporate datacenters, there are others whose dynamic compute requirements make them appropriate for cloud-based deployment. For such applications, the challenge is to take advantage of the computing elasticity and economics of cloud computing without sacrificing the security that the information assets (e.g., databases, directories, repositories) gain from being located on-premises within the business' datacenters. To be a viable hybrid cloud solution, data must be kept secure, applications need not be re-architected, and clouds should be readily mobile.